Magnitude 3.2 earthquake jolts southeast Michigan

Earthquake occurred offshore from Monroe

Earthquake felt in Michigan on Aug. 21, 2020. (The United States Geological Survey)

DETROIT BEACH, Mich. – A magnitude 3.2 earthquake occurred just offshore from Monroe at 6:55 p.m. Friday evening. USGS officials initially reported the quake as a 3.4 magnitude earthquake.

Earthquake jolts Michigan on Aug. 21, 2020. (USGS)

Here is how the quake looked like on a seismograph:

Seismograph showing earthquake on Aug. 21, 2020. (WDIV)

The “Did you feel it?” map on the U.S. Geological Survey website shows that the quake was felt strongest, as you would expect, Downriver closest to the epicenter, and was felt as far west as US-23 and as far north Waterford.

3.2 magnitude earthquake in SE Michigan: Did you feel it?

USGS 'Can You Feel It' map. (USGS)

Although earthquakes are not common in Michigan due to the fact that we are not located near any of our nation’s major fault lines, they do sometimes occur, and are called “within-plate” earthquakes.

You may recall the 2015 quake near Kalamazoo, that was a 4.2 magnitude quake. The largest quake to occur with its point of origin in Michigan was a 4.6 quake in 1947 near Coldwater. If you were in the Lansing area in 1994, you may have felt a 3.5 magnitude quake there. Those biggies that we hear about generally occur along faults, the boundaries between massive slabs (“plates”) of rock way beneath the earth’s surface.

Those plates move a bit, and where the edges of two plates come in contact, pressure builds up until one plate suddenly “slips” and slides along the other plate, or one suddenly slides above or below another. By the way, there is a science called “plate tectonics” which studies these plates and their movement.

Remember that the magnitude scale we always talk about is logarithmic scale? Each increase of 1.0 on the scale is ten times more force. So, when you hear about a magnitude 7.4 quake, that’s 10,000 times more forceful than the quake that occurred here this evening.

View Tweets below of what some residents say they felt:

About the Author:

Local 4 meteorologist Paul Gross was born in Detroit and has spent his entire life and career right here in southeast Michigan. Paul has researched, written and produced eight half-hour documentaries for WDIV, as well as many science, historical and environmental stories.